Cyclone separator



Oct. 29, 1940. c. c. MARsToN CYCLONE SEARATOR mea Feb. 2a, '194 2 Sheets-Shed l v l /M/E/vroaA CH/VDHCE. C. MAE@ TOM 35' Une/.M www Patented Oct. 29, 1940 UNITED STATES PATENT OFFICE Application February 28, 1940, Serial No. 321,339 In Great Britain February 18, 1938 2 Claims.

This invention concerns cyclone separators wherein dust, granular or pulverized materials borne on air or other gaseous currents are separated either or both for the purpose of cleaning the air or gas stream, or for obtaining the solids collectively, individually, or in graduation. For example grain or materials exhausted or extracted during the processes of cereal cleaning and milling may be so treated, or pulverized substances separated to obtain various degrees of particle grading from a very fine impalpable powder upwards. For convenience the solids will be referred to herein generally as dust, and air will be cited as the conveying current. The invention refers particularly to separators of the well known cyclone type wherein dust laden air is introduced tangentially to a separating chamber underpressure or by suction so as to be swirled around the chamber and expanded with the result that the centrifugal force set up causes the dust to be separated from the air, and the invention has for its objects a higher degree of, and if desired, selective separation in a shorter time and with relatively greater economy of apparatus than has hitherto been possible. In achieving these objects the invention employs the known arrangement of transferring dust laden gas from one separator to another' so that separation is e'ected in stages.

According to this invention there is provided at least two cyclone separator units having separating chambers provided with air discharge vent tubes'depending thereinto and separate from inlet and outlet orices, in combination with a transfer passage connecting an outlet orifice of one chamber with an inlet orifice of the next chamber and separate adjustable closure means for controlling the flow of air or other gas through the transfer passage between the two separating chambers and through the vent tubes respectively. The flow control means for the transfer passage may take the form of a slide or slides which can be moved transversely or vertically of the transfer passage to vary the size of or completely close the opening thereof. Thus by suitable adjustment of the closure means of the vent tube of the rst separator unit and of the transfer passage connecting the two units a proportion of the air admitted to the rst unit may, after suitable cleansing as a result of the centrifugal action and expansion, pass through the vent tube of that unit, whilst the remainder passes to thesecond unit throughthetransfer pas.- sage; thus a selective and a finer degree of separation may be eected. The plant, however, can be converted to an ordinary single cyclone separating unit, whenever desired, by completely closing the transfer control means and operating the first unit of the series alone. 'I'he foregoing are merely indicative of the great variety of .methods o f oper* ating the plant, depending of course on the materlals under treatment and the classiflcation desired. Another example of operation is `to shut off all vent tubes excepting the last.

In order that the invention may be readily understood one practical embodiment thereof will now be described with reference to the accompanying drawings in which:

Figure 1 shows diagrammatically in vertical elevation a device employing three identical separator units capable of being interconnected so as to give three successive stages of separation;

Figure 2 is a diagrammatic plan;

Figure 3 isa view similar to a part of Figure 1 showing a variation described later.

There are three units A, B and C arranged side by side with their vertical axes in one plane, although a staggered disposition may sometimes be 'found advantageous. Each unit is identical in shape, form and essential features and comprises a cylindrical separator chamber I, terminating at its lower end in a conical dust collecting hopper 2, and having a-centrally or eccentrically disposed internal vent tube 3 which may bel closed or through which cleaned air may be discharged either to atmosphere or to further cleaning and separating means, and which is provided with an adjustableclosure, e. g. a butterily valve 4. The lower end of the hopper 2 is furnished with any suitable adjustable closure for controlling the discharge of the separated dust.

Dust laden air is introduced under pressure or by suction tangentially into the upper part of the cylindrical separator chamber l lof the unit A, through an inlet pipe 5 which terminates in an inlet orifice 6. The inlet pipe 5 may be provided with the usual adjustable closure, and may incorporate bailles of triangular or 'other section or may be riiled for separating, disintegrating or otherwise preliminarily treating the. dust-laden air.

Between each pair of units there is a transfer' passage 1 which connects an outlet orifice 8 of the preceding separating chamber with an inlet orifice 9 of the following chamber, this transferr passage, as shown, being conveniently inclined across the plane containing the vertical axes of the units, with the result that gas passing therethrough from one chamber to the next reverses its direction of flow in the latter withrespect to that of the former. The space between adjacent chambers I may be comparatively small; for example the circles comprising the outer surfaces of It will be clear that 'the cross-sectional area of the transfer passage l may be of any suitable dimension, and in this respect it may be advantageous, according to the dust under treatment, to make it large, e. g. circumferentially subtending an angle of 30 or more at its mouth and, ln height. taking up the greater part of the depth of the cylindrical chamber I, as shown.

For the purpose of controlling the flow of dust laden air through each transfer passage 1, there is provided a slide I which in the example shown in Figures l and 2 moves transversely of the passage to reduce or increase the opening thereof as may be desired. This slide moves in guides II which may be felted or otherwise packed to prevent leakage of air or dust passing through the passage, and in the form illustrated consists of a a. plate having an aperture corresponding with the size of the transfer passage section; movement of the slide in one direction gradually brings the aperture into a position coincident with the passage, and in the other direction, causes a progressive blocking of the transfer passage. 'I'he said control vslide l0 may be shaped other than flat as illustrated, especially Iin the form where the passage is shortened by bringing the cylindrical bodies I close together as hereinbefore described. For instance, it may be of arcuate form mounted to slide approximately on the interior or exterior of the circumferential wall of either the leading or following cylindrical chamber. In a modification, employing arcuate slides, a pair of such curved control slides are employed, one on each of the cylindrical bodies l to be used either in unison (meeting at the centre) or independently. In Figure 3 there is illustrated a form where the slide I0a operates vertically.

The control slide, whatever its general shape or method of mounting, may be slotted, perforated or meshed over the whole or part of its operative area to form a screening surface.

In order that the separation action may be varied in the respective chambers 1, the vent tube 3 is provided with an extensible lower end in the form of a sleeve I2 which can be adjusted axially of the tube by means of operating rods I3 so as to raise or lower the inlet opening of the vent tube within the separating chamber, the sleeve in the fully extended position shown, disposing the inlet opening of the vent tube within the top part of the conical dust collecting hopper 2. The vent tube 3 may discharge into branched oultets, for example into three separate tubes, and, whether one or more are used, the actual exterior discharge section or sections may be made of airpermeable material.

In the embodiment shown the outlet orifice 8 of the third unit C is blanked off, but it will be understood that this unit may be connected to a further unit and the latter in turn to another unit and so on, if a further stage or stages of separation is required.

Arrangement may be made whereby any part or the whole of the air coming from the vent tubes may be re-circulated through any one or more of the separator units, and a separate inlet pipe 5 may be furnished for each or some of the units following the first, the invention providing for single or multiple stage separation as may be desired and for directing and controlling the flow and separation to the best advantage for the particular materials and operations concerned.

A supplemental air stream or streams maybe introduced into any or all of the cyclone units in addition to the main stream of dust-laden air fed in for treatment through the pipe l or trunk. For example, there is shown a supplemental pipe la which delivers air in the same direction as that fed in pipe l although at a lower level in the cyclone.

This supplemental stream may be purely air or other gas or it may be a branched or separate stream of dust-laden air. The object is to provide a means whereby the behaviour of the main dust-laden air stream within the cyclone may be controlled within wide limits according to the predetermined direction, quantity, and velocity of the supplementary air stream relative to the main stream. It may be introduced into the cyclone at any desired point either above, below or level with the main stream and directionally so as to augment, to diminish, or to deflect the main stream.

It will be readily appreciated that the supplementary stream may be used in several ways. By way of example it may -be directed so as to enhance centrifugal force by increasing the swirling action of the main stream in the upper part of the cyclone or to assist the settlement of separated matter by opposing the swirling action in the lower part of vthe cyclone. In the example illustrated a further searching swirl for extracting the lighter particles is given to the descendingmaterial after the centrifugal force due to the main stream from pipe 5 has decreased. Thus, in this case, the supplementary stream moves in the same direction as the main stream and against the downward movement of the separated matter so as to allow any desired heavier particles to fall and to keep the lighter particles riding in suspension and then to cause such lighter particles to leave the cyclone by the outlet 3 so as to be discharged either to atmosphere or to further treatment, which may consist of introduction into the additional cyclone or cyclones B and C or other cleaning means whereby complete or further discriminating separation may be effected. Alternatively or in addition the lighter particles or a proportion thereof may be transferred to a succeeding cyclone through the transfer passage 1.

The air inlet 6 from the pipe 5 and also the inlet from the pipe 5a may be valve-controlled to shift the plane in which the swirling current is introduced.

I claim:

l. A cyclone separating plant comprising at least two cyclone separator units each including a separating chamber having a tangential side inlet oriflce, a tangential side outlet orifice and an axial air outlet vent tube depending into said chamber, the side outlet orifice of one of said units being connected with the side inlet orifice of the other of said units, valve means for regulating the venting of air through said vent tubes, and other valve means for regulating flow of air through the connected together air outlet and air inlet orifices of the respective cyclone units.

2. A cyclone separating plant as set forth in claim 1 including means for introducing into the separating chamber of at least one of the cyclone units an air stream separate from the air stream entering said chamber through the side inlet orice thereof.

CANDACE CHARLES MARS'I'ON. 

